Hello',
You should maybe think about adding rank to your system as you only have a few.
Apparently there are no officers ranks (by officers I mean ranks under leadership ranks).
The thing is, if player are getting a high rank too fast (whiuch could be due to a lack of ranks), they could loose interest as it'd be too easy.
On another hand, if you tell me the promotion system will be slow, people could also loose interest as they'd be stuck on their rank for a long timd.
In addition of that, it's always good to have 4 times of ranks: Rankers, Sub Officers (Juniors), Officers & Leadership.
That said, good luck
.